Transform domain channel estimation in comb type pilot aided OFDM systems

Aimed at non-integer-sample spaced OFDM systems, an improved DFT-based channel estimation method for comb-type pilot OFDM systems is proposed, which can diminish noise effectively and recover the dispersive distortion of estimated channel impulse response (CIR) caused by non-integer-sample space delay spread by choosing proper the zero-padding position. In addition, for low SNR environment, ignoring that non-important channel taps containing more noise than channel power energy can lead to more performance improvement. Simulation and analytic results show that the improved channel estimation method is better than frequency-domain interpolation methods and conventional zero-padding methods and is promising for practical engineering applications with good performance and low complexity.